Long, Long ago in a galaxy far, far away, there existed a superpower that was made up of seven tribes. This nation was led by a king who was selected from one of these tribes by through ritual combat. Potential heirs would meet in a king-of-the-hill style process which would pit them against each other to prove their strength and prowess to their people, demonstrating their ability to defend the country from outside threats. The ones killed in battle would join their honored ancestors while the winner would be crowned king.
Every leader needs a security force to protect him from inside and outside threats, this nation being no exception. However, a tradition arose in the past revolving around the use of bodyguards. Males were forbidden to serve in this capacity, forcing the personal guards of the king to be made up of all women. These females, called the Amazonian brigade, would receive the same training and access to weaponry of the military, and be the king's shadow at all times. Like traditional security forces, these women would handle all personal security threats aimed at the king, were privy to the highest, unclassified information, and were to sacrifice their lives for him if necessary.
Seeing as how men are generally, bigger, stronger, and faster, it would make more sense for males to be assigned to such an important role from a defense perspective. The only example in real life of an all-female bodyguard system was Omar Quadaffi, leader of Libya, whoose "security force" were more akin to sex slaves that he took a fancy to, and they ultimately failed to protect him from being brutally killed.
What advantages would an all female-force have over traditional male bodyguard forces to justify their usage?